Automatic safety control for air-brake systems



June 19, 1923.

L. F. HELLMANN ET AL AUTOMATIC SAFETY CONTROL FOR AIR BRAKE- SYSTEMS 5Sheds-Sheet 1 Filed May 10". 1920 INVENTORS 10/ F, HELL/VAN W/LL/HM M819x 2.

BY xii/6W3 ATTORNEY- June 19, 1923.

L..F. HELLMANN ET AL AUTOMATIC SAFETY CONTROL FOR AIR BRAKE SYSTEMS 5Sheets-Sheet 2 Filed May 10, 1920 INVENTORS 1w /7 Hag/warm BY Win/4M JV.mmm

' ATTORNEYS June 19,- 1923. 1,459,098

L. F. HELLMANN ET AL AUTOMATIC SAFETY CONTROL FOR AIR BRAKE SYSTEMS June19, 1923. 1,459,098

' 4 L. F. HELLMANN ET AL AUTOMATIC SAFETY CONTROL FOR AIR BRAKE SYSTEMSFiled May 10, 1920 5 Sheets-Sheet 4 FIQ. 11' m PIE Z 13 a 4 3a 5 D 90 9|g5 90* i INVENTORS 92 85 g v' 40/ EHELLM/ /Y/y.

L A/P h/MLMM W. 5A0":

June 19, 1923. 1,459,098

L. F. HELLMANN ET AL AUTOMATIC SAFETY CONTROL FOR AIR BRAKE SYSTEMSFiled May 10. 1920 5 Shegts-Sheet 5 a I F I Il6-:;- z 6 I22 v w 137g 38r- I" fllrlllll lll l g zll ATTORNEYS.

Patented .lune 19, 1923.

lelhlll Iji Ltd,

lFlQ.

LUI F. HELLMANN AND WILLIAM 1V. BAXTER, OF INDIANAPOLIS, INDIANA,ASSIGNORS TO AIR BRAKE SAFETY APPLIANCE COMPANY, OF INDIANAPOLIS,INDIANA, A

CORPORATION.

AUTOMATIC SAFETY CONTROL FOR AIR-BRAKE SYSTEMS.

Application filed May 10, 1920.

To aZZ w from it may concern Be it known that we, LUI F. HELLMANN andVVILLIAM -W. BAXTER, citizens of the United States, and residents ofIndianapolis, county of Marion, and State of Indiana, have invented acertain new and useful Automatic Safety Control for Air-Brake Systems;and we do hereby declare that'the following is a full, clear, and exactdescription thereof, reference being had to the accompanying drawings,in which like numerals refer to like parts.

This invention relates to pneumatic braking system, wherein the wheelsof a vehicle are equipped with pneumatically operated brakes, and meanscontrolling the pneumatic braking system as well as the power system ofthe vehicle.

This invention is an improvement upon the co-pending application SerialNo. 297,107, filed May 14, 1919, allowed November f, 1919 and patentedMay 18, 1920, Number 1,340,861, and relates to safety appliances forpneumatic braking system used on steam, electric, street railway,- andother vehicles which usually is of the straight air or automatic airtype.

The main object of the invention is to provide the air brake system withsafety control means whereby the human factor in the operation of avehicle to which the automatic safety control appliances have beenapplied, is eliminated during such times as the vehicle shall havebecome dangerous and a menace to public safety by virtue of some failureof the air brake system.

One chief object of the invention is to provide safety means forautomatically controlling the vehicle when through carelessness neglect,or thoughtlessness, on the part of the operator, the vehicle shall havebecome a menace to public safety.

Another chief object of the invention is to provide safety control meanswhich will prevent the operation of the vehicle unless the brakingsystem shall be in a safe and operable condition.

A further object of the invention is to provide safety control meanswhich, if tampered with, will prevent the operation of the vehicle.

Another object of the invention is to provide control means forpreventing power Serial N0. 380,234.

from being supplied to the driving means of the vehicle until such timeas the air brake system has been charged with sufficient compressed airto insure the safe operation of the brakes on the vehicle.

Another object of the invention is to pro vide the safety powercontrolling means with additional means whereby the operator, only bywilfully and intentionally manipulating said additional means, maysupplv power to the driving means of the vehicle, whether the brakesystem is in an operable condition or not: but said additional means isonly operable after the intentional act of the operator has beenrecorded by the break ing of suitable seal means or by operating someother suitable recording means.

A further object of the invention is to construct the safety controlmeans in such a manner that the failure of any vital part thereof willcause the brakes to be applied and simultaneously shut ofi the powerapplied to the driving means of the vehicle.

Another object of the invention is to provide means which will preventthe further operation of the vehicle, after the automatic safety controlhas caused the brakes to be applied and the power has been shutoff fromthe driving means of the vehicle, until such time as the defect whichcaused the automatic safety control to function has been repaired orproper safety precautions have been taken.

One feature of the invention consists in substituting suitablepneumatically oper ated means for the electric solenoid means shown inour patent hereinbefore referred to.

Another feature of the invention consist in substituting a suitablepneumatic circuit in providing suitable pneumatically controlled meansfor controlling the automatic air brake triple valve exhaust portAnother feature of the invention is the provision of means associatedwith the circuit breaker or powercontrollmg means and the auxiliarysource of pressure so that when it is desired to operate the vehicle thebrakes may be simultaneously released and the circuit breaker operably.positioned after the foregoing have been actuated by a mechanical orpneumatic failure.

Thefull nature of the invention, including objects and features notenumerated, will be more readily understood by reference to theaccompanying drawings and the following description and claims In thedrawings Fig. l is a plan view of an electrically propelled railway caror coach to which the preferred and selected embodiment of the automaticsat ety control has been applied, and in this instance the brake systemshown is what is technically known as a straight air brake system.

Fig. 2 is a diagrammatic elevational view of the same showing inparticular the pneumatically controlled circuit breaker and the safetycontrol mechanism associated therewith.

I Fig. 8 is an enlarged perspective view of the operators air brakecontrol valve, automatic safety control valve, and connections theretoand therebetween as illustrated in Figs. 1 and 2.

Figs. 4 and 5 are. central sectional views taken along the horizontaland longitudinal axes of the automatic safety control valve shown inperspective in Fig. 3 and illustratesv the parts in two extremepositions. In Fig. 4 the parts are shown in the position assumed by thesame when the brakes have been applied. while in Fig. 5 the parts are inthe brakereleasing position.

Figs. 6 and 7 are partial, central, vertical sectional views taken onthe line 66 of Fig.

4 and the line 7.7 of Fig. 5 respectively.

Figs. 8 and 9 are transverse. central sectional views taken on the line88 of Fig. 6 and line 9-9 f Fig. 7 respectively. Fig. 8 illustrates theparts in the position assumed when the brakes have been applied and thepower controlling means locked to prevent power being supplied to thevehicle.

Fig. 9 illustrates the same parts in the brake releasing position whichplaces the power circuit controlling means in operative con dition.

F ig. 10 is a view similar to Figs. 8 and 9 showing the position assumedby the parts v after the breaking of the operating spring means orfailure of the spring mechanism which is substantially equivalent ineffect upon. the circuit breaker as when the parts are in the positionshown in Fig.1)".

Fig. ll is a sectional view of a circuit breaker provided with pneumaticcontrolling means, showing the parts in the pneumatic controlled closedcircuit position.

Fig. 12 is a similar view showing the parts in the circuit breaking oropen circuit position after the pneumatic safety control means hasoperated.

Fig. 1% is a view similar to Figs. 11 and 12 showing the circuit breakercontrolling parts maintained in the closed circuit position after themanual controlling means has been manipulated, whereby the operatorintentionally permits power to be applied to the driving means of thevehicle.

Fig. 1.4- is a side elevational view oi the circuit breaker illustratingadditional and independent manual manipulating means, which is a part ofthe circuit breaker, in circuit breaking or open circuit position.

Fig. 15 is a diagrammatic view of the invention when applied to anautomatic air brake system, including the automatic safety control, thetriple valve exhaust port control. valve and the auxiliary reservoir,said parts being shown in the brake releasing position with theexhaust'port control valve, brake cylinder and auxiliary reservoirthereof being shown in section.

Fig. 16 is a central sectional view of the.

triple valve exhaust port control valve in the closing position.

In Figs. 1 to 14' inclusive the preferred embodiment oi? the inventionis illustrated and will be described as applied. to a straight air brakesystem.

In Figs. 15 and 16 the same embodiment of the invention is illustratedand will be described as applied to an automatic air brake system.

In Figs. 1 and 2, 20 indicates an electrically propelled vehicle, coachor car provided with wheels 21. the car being equipped wi h foundationbrake mechanism, not shown. Suitably positioned upon said car is theusual brake cylinder 22 supplied in this instance with compressed airfrom an air storage reservoir 23, said reservoir being supplied with airby a suitable pump mechanism 24 or from stations suitably positionedalong the line of operation of the vehicle. Suitable conduit means 25and 26 connect the air storage reservoir 23 and the brake cylinder 22respectively to the operators valve 27. In Fig. 1 the vehicle is alsoshown provided with a suitable hand brake 28 and the motor powercontroller 29, all of which are of the usual construction.

In Fig. 2 a circuit breaker 30 is shown provided with a manuallyoperated rod member 31 and pneumatic controlling means 96 ispneumatically connected by means of a conduit 32 to the improvedautomatic safety control valve 33. In the present instance the solenoid5 and the solenoid 21 of the patent hereinbefore referred to issubstantially replaced by pn'aumatic circuit means hereinafter to bedescribed.

As shown in Fig. 3 the regular operators valve 27 is provided with theusual pressure indicating means 34 and the conduit 35 which exhausts tothe atmosphere. Also the usual cut-out cock 01 valve 36 is provided inthe supply line 25 and the casing of the operators valve 27 is suitablynotched as at 43 and 44 to indicate the various positions assumed by thehandle 42. A suitable bypass conduit 37 is in communication with thefeed line 25 before the same enters the operators valve 27. The conduit37 also communicates with the automatic safety control valve 33 and,through means therein and hereinafter to be described, with the conduit32, 38, and 26 (see Fig. 3). The conduit 32 connects the automaticsafety control valve 33 with the pneumatic circuit breaker control 96(see Fig. 2). The conduit 38 (see Fig. 1) connects the automatic safetycontrol valve with the auxiliary reservoir 39, while the conduit 26connects the automatic safety control valve with the brake cylinder 22(see Fig. 1). In Fig. 3 a suitable conduit 41 also connects theoperators valve27 with the automatic safety control valve 33. v

As illustrated in Figs. 1, 2 and 3 air from the storage reservoir23 issupplied through the conduit 25 to the operators valve 27 and by theusual manual manipulation of the handle 42, (see Fig. 3) may bepermitted to flow through the conduit 41, and by means to be hereinafterdescribed through automatic safety control valve 33 and conduit 26 tothe brake cylinder 22.

The improved automatic safety control valve is shown, in detail in Figs.4 to 10 inclusive in which 33 indicates the valve casing or body, 33 abushinsr, 33 suitable packing to prevent leakage around said bushing,and 33 a cap or nut for retaining said bushing and packing within thecasing and upon the shoulder 33. )Vithin the bushing 33 is a port 41communicating with the conduit 41. The reduced inner end of the bushing33 is tapered inwardly to form a receiving valve seat 63 for a suitablepiston valve member 45, the latter having ports 62 and 64. Also withinthe casing member 33 is a chamber-47 communicating with chamber 47 awhich in turn communicates with the conduit 26. The chamber 47communicates with the chamber 47 8 within the bushing 33 through theports 64, when the parts are in the position shown in Figs. 5, 7 and 9.A chamber 49, in the casing 33, is in communication with the chamber 48through the port 49, chamber 50 and port 50, Figs. 4, 5, 6 and 7. A

chamber 59 communicates with the chamber 48 through the conduit or port58, Figs. 4 to 10, by means hereinafter to be described. The chamber 48is in direct communication with the main supply line 25 through the.

nication with chamber 47 b through the ports 64 when the parts haveassumed the position shown in Figs. 5, 7, 9 and 10. Suitable packing 61and packing nut 61', Figs.

4-and 5, prevent leakage around the piston rod 61 between the chambers49 and 59.

Within the chamber 59, Figs. 4 and 5, is

a suitable piston member 60 positioned on the rod member 61 and isadapted to seat at 66 on the chamfered inner end oft-ho cap member 66.The piston 60 is provided with suitable ringpacking 69 and is cored outto receive a pair of concentric'helical springs 68 and 69. To preventleakage be tween the piston rod 61 and piston 62, suitable packing 60*and a packing nut 6O are provided.

The cap 66 has an opening 67 in the end communicating with theatmosphere and is suitably cored out to receive one end of the spring68. The other concentric spring 69 is; of proper tension to hold thepiston valve 45 on its seat 46, (see Fig. 5) in the casing): member 33,against the pressure in the chamber 49 but permits the piston 60 to moveto its seat 66 on the inner end of the cap 66 when operating airpressure is supplied to the chamber59. The spring 68 is of su'l iicienttension to hold the piston valve member 45 on its seat 63, as shown inFief. 4, during such times as there is not suiiicient pressure in thechamber 59 to overcome the pressure of said spring 68. The rod 61 isherein shown shouldered at 61 to permit the piston 60 to engage saidshoulder (se 4), to move the piston valve member 45 to the seatedposition.

The means for connecting the chamber 59 tothe chamber 48 comprises abushing 53, (Figs. 6 to 10 inclusive) within the casing member 33. andsuitably packed against leakage at 53*. The bushing 53 is held in placeby a hollow elongated nut 71. The

bushing 53 is slotted to form the superposi-: 1

tioned ports 57 and 70, (see 8. 9 and 10) which at all times are in freecommunication with the passage 58. Also within the bushing 53 are thevalve seats 53 and 81- with the port 54 therebetween communicating withthe chamber 48.

The inner end oi? the'elongated nut '71 is tapered to form a suitablevalve 73, (see Figs. (Sto 10 inclusive) and the lower hollow end of saidnut is internally threaded to receive the check nuts 77 and 77", whichsecure the helical spring 76 in the chamber 7 2. The nuts Ti and '77each have an opening '78 registering with an opening 80 in theprotecting cap member 7 9, whereby the chamber 72 communicates with theatmosphere.

The bushing 53 is bored out to form a chamber 55 within which is theother check valve 56 having one endadapted to seat at meut with a seat75 in the check valve 56 and held in this position by the helical springTO. A. rod 82 upon. the check valve 75 extends "upwardly and looselythrough a port"74,

the same extending through said check valve 56. Sand rod extends throughthe chamber 55 and through the registering port 54 into the chamber 48and carries on its upper end a valve 83 which is adapted to seat at 81,see Fig. 10. It will be noted that the rod 82 is of suiiicient length tohold the check valve 83 oil? the seat 81 when the check valve 56 isseated at 73 as in Figs. 8 and 9.

The helical spring '76 holds the slidable check valve 56 on its upperseat 53 during such times as the air pressure in the chamber 55 is lessthan the tension of said spring.

lVithin the chamber (see Figs. '6 and 7) is a check valve member 51 heldagainst its seat-5O by a spring 52. The outer end of the chamber-50' isclosed by suitable pack.- ing 52 and a nut 52 which is bored out at 52to receive one end of the check valve stem 51. The opposite end of thevalve stem 51 extends through the chamber 48 and'is receivable in aguide slot 51 formed in the casing member 33.

The operation of the autou'iatic safetycontrol valve will be describedwith suitable reference to the accompanying drawings and the foregoingdescription, so that the same will be readily understood.

The parts are normally positioned as shown in Figs. 4 and 6. Compressedair from the reservoir 23. (see F igs. 1 and 2) passes from the conduit25 into the bypass conduit 37 and also into the operators valve 27. Theair entering the conduit 37 first passes into the chamber 48 (see Figs.6, 7, 8 and 9) and is then directed to a plurality of means. Thespring52, in the chamber 50*, having only sufiicient tension to hold the valve51 on its seat, is forced open by the pressure 01 the air entering thechamber 48 which permits the compressed air to; pass through the port 49into the chamber 49. Since the chamber 49 isin communication, throughthe conduit 38, with the auxiliary reservoir 89 air pressure would buildup in the auxiliary reservoir 39 until the pressure in the same wasequal to the pressure in the storage reservoir 23.

As the iston valve 45 is normally positioned as shown in Fig. 4, becauseof the pressure exerted by the spring 68' on the piston 60 and the airpressure in the chamber 49, air passes through the ports 62 in thepiston valve 45 into the chamber. 47. Since the chamber 47 is always incommunication with the chamber 47 and with theconduit 26, air wouldenter the brake cylinder 22 until the n'essure in the brake cylinder 22was equal to that in thereservoirs 23 and 39, thus causing the brakes onthe vehicle to be applied in the usual manner; I

Another portion of the air supplied to the chamber 48 passes through theport 54, in the bushing (see Figs. 6 to 10 inclusive) into the chamberand when sufficient pressure has accumulated in the chamber 55 2 toovercome the tension of the spring 76,

the check valve 56 is forced from its seat 53' (see Fig. 6) andintoposition to seat at 73,

(see Fig. 7) on the inner end of the 6lOI1 gated nut 71. This movementof the valve Y 56 closes the port 70, which is normally in communicationwith the atmosphere through the chamber 72, and places the port 57 alsoleading into the passage "58, in communication with the chamber 55whereupon the compressed air passes through the passage 58 into thechamber 59.

Since the area of the piston.60' exceeds that of the piston valve 45 andthe pressures in chambers 49 and 59 are equal, the piston 60 compressesthe spring 68 and seats itself at 66, (see Fig. 5). Simultaneously thepiston valve 45, carried by the rod 61, would be caused to seat at 46,by virtue of the tension of the spring 69 which, as previously explainedis strong enough to overcome the oppositely directed pressure in thechamber 49 against the piston valve'45.

This action cuts ofi communication between the chambers 47 and 49, byclosing the ports 62, and establishes direct communication between thebrake cylinder 22, see F ig'. 1, and the operators valve 27, through theconduit 26, the chamber 47*, the chamber 47, ports 64, chamber 47?, port41 and conduit 41 (see Fig.5). By manual manipulation of the lever 42 ofthe operators valve, see Fig. 8, the air in the brake cylinder isreleased, causing the brakes on the vehicle to be released in the usualmanner.

After the brakes have been released the car or vehicle is in operativecondition and the parts of the automatic safety control valve remain in'the position shown in Figs.

5, 7 and 9 until some defect causes the air pressure in the chamber 48to fall below the pressure exerted by the spring 76 on the check valve56 whereupon the check valve 56 is forced from its seat 73 and seats at53*.

The foregoing movement o the check valve 56 cuts oil communicationbetween the chamber and the port 57 and establishes communicationbetween the chamber 59 and the atmosphere, through the passage 58, port70, chamber 72. ports 78 and port 80, see 6 and 8, thus releasing allpressure against the piston 69 whichagain assumes the position shown inFig. 4, by virtue of the pressure of the spring 68 against the piston 60aided by the air pressure against the piston valve in the chamber 49.and the piston 60, from the position shown in Fig. 5 to that shown in 4,closes communication between the operators valve 27 and the brakecylinder 22 by causing the piston valve 45 to seat at 63 thus closingthe ports 64, which prevents the operator from uitertteriug. with theoperation of the auto matic safety control valve.

As previously explained when the parts have assumed the position shownin Fig. 4, direct communication is established between the auxiliaryreservoir 39 and the brake cylinder 22 through the conduits 38 and 26,thus applying the brakes on the vehicle. it will be remembered that thepressure in the auxiliary reservoir 39 was built up to a pressure equalto that carried in the reservoir 23 and any escape from the reservoir 39is prevented by the action of the spring 52,

which, when the pressure in the chamber 48 is less than that in theauxiliary reservoir, causes the check valve 51 to close the port 50,thus preventing any air from flowing into the chamber 48 from thereservoir 39.

Since the parts have again assumed their normal position, as shown inFig. 4, and can only be placed in operative position by the storing ofsutiicient pressure in the reservoir 23 and the chamber to overcome thepressure exerted by the spring 76, it is evident that the communicationbetween the brake cylinder 22 and the operators valve 27 will be closedand the brakes will remain applied until the defect which caused thefailure is repaired. or proper safety precautions taken, as'will beexplained later.

As previously stated one of the objects of this invention is to preventthe operation of the vehicle should any of the operative parts t theautomatic satiety control valve be broken or tampered with. If duringthe normal operation of the vehicle, the parts then being in theposition shown in Figs. 5, 7 and 9, should any vital part of the safetycontrol valve become broken or loose, the valve means would operateapply the This movement of the piston valve 45' brakes. Thus if thepiston valve 45 become detached from the rod 61, the air pressure in thechamber 49 would force the piston valve 45 from its seat 46 and cause itto seat at 63. therebyopening the passage from the auxiliary reservoir39 to the brake cylinder 22 previously explained.

Should the rod 61 break, the spring 69 break. or the nuts 69 becomeloose, there would be no means to hold the piston valve upon the seat46, as shown in Fig. 5. If the cap 66 were loosened or removed the airin the chamber 59 would leak past the seat 66 and packing since thelatter would then be unsupported and the piston valve 45 having nothingto hold it upon the seat 46 would function again.

Although the removal of the cap'79 would iave no effect upon theoperation of the valve, the removal of the nut 71, however, reduces thetension of the spring 76 or removes the same entirely, and this causesthe check valve 88 to seat'at 81, see Fig. 10, and prevent the escape ofair from the chamber 48. Since the valve 56 with the removal of said nutwould have no seat as at 73, air would leak from the port 57 into thechamber 55, then past the valve 56 and through the port 74 and exhaustthe pressure in the chamber 59 thereby causing the valve 45 to operateas heretofore described.

T he removal of the check nuts 77 and 77 or the removal of, or thebreaking of the spring 76 would cause the parts to assume the positionshown in Fig. 10 and the air 'in the chamber 59 would exhaust to theatmosphere through the passage 58, port 51?, chamber 55, port 74 andchamber 72, thereby causing the valve 45 to operate in the mannerpreviously described.

As hereinbefore stated the passage 58 communicates with the circuitbreaker control 96 by means of the conduit 82. From the Followingdescription and by reference to Figs. 11 to 14 inclusive the circuitbreaker control will be readily understood. The circuit breaker control96 is illustrated in detail, but the actual circuitbreaking means 30 isomitted, since any convenient circuit lnrcaking means may be suitablyconnected to the actuating means herein disclosed.

T he circuit breaker control 96 is attached to the usual circuitbreaker30 by means of suitable supports 30 and 30* and a transverse bracketmember 87. The control supporting means is held.in place by suitablelock nuts 91 and consists of a casing member 91 chambered to receive aspring 89 and piston 90. the latter being provided with suitable packingmeans or rings 95. The piston member 96 is in the form of a valveseatable at 90 Attached to the piston 90 and projecting through thechambered casing 91 is a rod member 88 having upon its extreme. end thelock nuts 92.

A locking lever or latch 84, which is part ofthe circuit'breaker ispivotally supported at 84 and carries upon one end a bushing 93 thelatter being held. in place by the nut 93 and being insulated from thelever 84 by suitable insulation means 93*. The open-' ing through thebushing 93 is large enough to permit the lever 84 to rock or tilt uponits axis 84 independently of the rod 88, see Figs. 12 and 14. The lever84 carries a latching projection 85 adapted to'engage the pawl 86,attached to the handle 105, see Fig.

. 2, all of which are parts of the circuit breaker 30 and are providedto permit the operator to place the circuit breaker in circuit closingposition.

The means for manually operating the cir cuit breaker 30 is clearlyshown in Figs. 2 and 11 to 14 inclusive. The push rod 31 is slidablysupported by the circuit breaker casing 80 and the free end thereoftermi- .nates within said casing adjacent the lever 84. The'circuit isopened by striking the outer end of the rod 31, whereby the inner end isbrought in contact with the free end of the lever 84 causing it to tiltthe same and raise the latching projection from en gagement with thepawl 86 which releases the circuit breaking means to open the powercircuit.

Attached to the casing member 91, of the 1 circuit breaker control 96,is a bushing or cylinder head 94 provided with a chamber 94 whichcommunicates with the conduit 32.

' enough to pass lengthwise through the elongated slot 103. The pinnormally rests on the outer end of the cap 99 and maintains the rod 97in the position shown in Fig. 11. The cap 99 also has a hole 99 at rightangles to the slot 103, and the rod 97 has a hole 98 in alignment withthe hole 99 to permit a pin 98 to pass through the cap 99 and rod 97 tohold the rod 97 in the position shown in Figs. 11 and 12..

In the outer end of the pin 98 is provided a hole through which a wire101 is passed and a suitable seal 100 may be affixed. The

rod member 97 also carries the handle or insulating knob 104.

As previously explained Figs. 11 and 13 illustrate the position assumedby the parts when the circuit is closed, or power is be ingsupplied tothe drivlng means of the Vehicle, and Flgs. 12 and 14 illustrate the her94.

there is no air pressure in the passage 58,

consequently there would be none in the conduit 32, which communicateswith the passage 58, see Figs. 8, 9 and 10. Since the.

spring 89 isof sufiicient tension to hold the piston 90 in the positionshown in Fig. 12,

when the chamber 94 is not under pressure,

the rod 88 will tilt the lever 84 and prevent theprojection 85 fromengaging the pawl 86. This prevents any power being supplied to thevehicle, through the regular source, since no matter how often thehandle 105, see Fig. 2, was actuated, the latch 85 is not in apositionto engage the pawl 86.

lVhen the partsof the automatic safety control valve 33 are in theposition shown in Figs. 5, 7 and 9, air would pass through the passage58 and conduit 32 intothe chaml Vhen sutiicient pressure has nocumulated in the chamber 94 to overcome the tension of the spring 89 thepiston 90 would be forced from the position shown in Fig. 12 to thatshown in Fig. lland seat at 90 which would permit the circuit closingmeansto be maintained in the circuit closingposition when the handle 105was actuated. v

Since no, air can enter the passage 58 until sutficient pressure hasbeen stored in thereservoir 28 and auxiliary reservoir 39 to insure salebraking power, the circuit controlling means w1ll be held open untilthis pressure is-attained. When the parts of the automatic safetycontrol valve 33 are in the position shown in Figsf4, 6 and 8, the airin the passage 58 is in communication with the atmosphere hence thepressure in the chamber 94 and conduit 32 would exhaust to theatmosphere, the spring 89 would cause the piston 90 to move upwardly anddisengage the latching projection 85 from the circuit controlling pawl86 to open the circuit. I

In the eventthat conditions aremet with, which would prevent theoperation of the air brake system or there maybe apneumatic or amechanical failure thereof; it may be desirable to operate the vehicle,and for this reason the manual manipulating means of the circuit breakercontrol is provided to maintain the piston 90 in the closed circuitposition, otherwise it would not be possible to supply power to thevehicle.

The operator, to permit power to be supplied to the vehicle through thecircuit breaker, or other power controlling means, therefore. mustintentionally operate the cir- Guit breaker control and record thisaction by the breaking of a seal or by the operation of some othersuitable recording means. By breaking the seal 100 and removing the wire101, the pin 98 may be removed from the cap 99 and the rod 97. Thispermits the rod 9'? to engage the upper end of the piston by turning therod 97 one quarter turn, whereupon the pin 102 will pass through theelongated slot 103 and enter the chamber 96 when by turning anotherquarter turn, so as to position the pin 102 at right angles to the slot103, the pin 102 rests on the in-- nor side of the cap 99, since thespring 89 tends to force the piston 90 outwardly. The movement of therod 97 passing from the position shown in Fig. 11 to that shown in Fig.13 is suflicient to cause the piston 90 to mechanically seat at 90 andpermit the projection 85 to be positioned to engagethe pawl 86 when theoperator operates the circuit breaker handle 105 to supply power to thevehicle.

Should the spring 76, or the conduit 32 break, or any serious air leaksdevelop therein or in the chamber 94, in the packing or lock 97 the airpressure holding the pi.s ton 90 on its seat 90 would fall below thepressure exerted by the spring 89 and the piston 90 would be forcedupwardly thereby causing the power to be shut off simultaneously withthe exhaustion of the pressure in the chamber 59, whereby the automaticsafety control valve would operate to apply the brakes. Consequently,should the automatic safety control valve operate to apply the brakesthe air in the conduit 82 would be exhausted causing the power to beshut off in the manner described.

Should the spring member 89 of the circuit breaker 98 break or fail tofunction it would not interfere with the normal oper ation of the car asthe piston 90 would be held in operative position by air pressure in thechamber 9 1.

It will be noted that the braking power upon any vehicle is usually ornormally greater in amount than the traction driving power, and shouldthe spring 89 break or fail the application of the brakes will bring thevehicle to a stop although the power is not shut ofl. But with thepresent type of circuit breakers, the overload coil thereof will opensaid breaker when the above over-- load resulting from the applicatimiof hr. brakes is produced. After this condition has occurred, thecircuit breaker control is always in position to be operated, so that.the handle may be actuated to again supply power to the vehicle, but aswill be remembered, the brakes on the vehicle will remain applied untilsuflioient braking built up in the system.

When a mechanical or pneumatic failure of the brake system has occurredit will be remembered that the power is automatically cut oli" from thevehicle and the brakes are applied by reason of the auxiliary source ofpressure. If the failure mentioned is such that suliicientln'akingpressure cannot be built up in the system or the original.source of pneumatic pressure, the brakes would remain applied and thevehicle could not be operated, since the usual overload circuit. breakerwould immediately open the power circuit because the braking power of avehicle in a stationary position usually exceeds the tfiaotive powerupon the same.

pressure is To operate the vehicle in spite of said failure requires therelease of the brakes, which means the bl eding or release of the auxiiary reservoir and brake system associated therewith, andthe'intentional operation of the circuit breaking control means 96 topermit power to be sup-plied to the vehicle.

To facilitate this last operation, means is in'ovided for simultaneouslyoperating the circuit breaking control means 96 and bleeding or drainingthe auxiliary source of pressure and associated brake system to releasethe brakes. This means compr ses a conduit or pipe connecting theauxiliaryreservoir 39, see Figs. 1 and 15, to the circuit breakercontrol 96. The conduit adiacent the reservoir 39, is provided withsuitable valve means such that should a leak or failure develop in 'theconduit or the means associated therewith, the reservoir could be cutoff from said conduit and function as heretofore described. stancehowever, a valve .139 is provided on the auxiliary reservoir, whichvalve may be used for cleaning purposes as well.

The means included in the circuit breaker control 96 associated with theconduit is shown in detail in Figs. 11., 12 and 13.-

in the position shown in Fig. 13, said-chair.

nel 237 being formed in the head 94, as shown. The other end ofthechannel 237 communicates with the conduit 232 such that when the pushrod is positioned as illus trated in Fig. 13 the auxiliary reservoir 39is permitted to exhaust to the atmosphere through the valve 233, conduit232, channel.

In this inresult.

237, ports 236, slot. 234 and slot 235. Suitable packing means 97 n andsecuring means 97 prevent leakage between the channel 237 and thechaml'ier 96 to the atmosphere and will be understood from the foregoingdescri-ption, since the actuation of thepush rod in the manner describedaccomplishes this The actuation of the push rod 97,

-however, it will be remembered, must be recorded by the breaking of aseal means or otherwise suitably recorded. The vehicle after the pushrod 97 has been actuated is released from the brakes, and the circuitbreaker permits power to be supplied to the vehicle as shown.

The foregoing specification has been described both as to structure andoperation, assuming that the parts were applied to a straight air brakesystem. In Figs. 15 and 16, however, the improved circuit breaker 30,the auxiliaryreservoir 39, and the air safety control valve 33 are shownincorporated in a regular automatic air brake system.

. In the automatic air brake system the essential parts of the regularequipment of a train consists of the following: an air compressor, astorage reservoir, an operators valve, an auxiliary reservoir, triplevalve and brake cylinder. The compressor, operatorsvalve and storagereservoir are usually located on the driving means of the train,

while each vehicle is equipped with a brake cylinder, triple valve andan auxiliary reservoir all ofwhich are connected to each other bysuitable conduit means in the reg ular manner.

The air compressor compresses the air and stores it in the storagereservoir from whence it flows through suitable conduit means throughthe operators valve to the triple valve on each vehicle. It is thenpermitted to flow into the auxiliary reservoir on the vehiclescomprising the train until an equal, predetermined pressure is built upin each auxiliary reservoir 40,

So long as the predetermined pressureis maintained in the auxiliaryreservoir the brakes on the train remain in the release position, butshould the pressure fall due to a failure of any of the equipment orthrough the operation of the operators valve, the triple valve on eachcar is caused to operate to permit air to enter the brake cylinder 7 andapplythebrakes on the train.

The automatic safetycontrol valve asused on the automatic air brakesystem is of thesame construction and operation as on the straight airbrake system except that the port tl is not required and is closed byreplacing the conduit 41 with a suitable plug The same power controllingmeans is used without alteration and itsoperation is the same as hereinbefore described.

F 15 is a'diagrammatic sectional view of an automatic air brake systemin which 110 indicates the. operators'valve, 25,,

133, 134 and 135 suitable conduit means connecting the storagereservoir, not shown, to the triple valve 112, auxiliary reservoir 40,and brakecylinder 22. Within the reservoir .40 is the conduit 1 10 whichconnects the automatic safety control valve 33, the circuit' breakercontrol 96, see Fig. 2, and the triple valve exhaustport control valve1441,

see Fig. 15. Leading from the chamber 19 of the automatic safety controlvalve 33 is the conduit 38 connecting the'auxiliary reservoir'39 asinthe straight air brake system. I

Fig. 16 is a sectional view of the triple valve exhaust port controlvalve 114 showing the parts in the exhaust port closing po sition andhaving a casing member 11 1, Within the casing 114k" is a port 118"connect-ing a chamber 117 with the triple valve exhaust port 113 by theconduit118. Leading from the chamber 117 is the ort 121, the

inner end of which is tapereo to form a valve seat 119 for the valve120'controlling said port. A rod member 123 extends through thepartition wall between the chambers 116 and 115 carrying the valve 120on one end and the piston 124 on the other end and in the respectivechambers. To prevent leakage between the chambers 115 and 116. suitablepacking 116 and packing nut 116 is provided. The chamber 116 is providedwith a port 122 which is preferably threaded to receive the usualretainer valve when the same is used, otherwise the port 122 dischar esdirectly into the atmosphere, as shown.

The outer end of the casing lli is interiorly and exteriorly threaded toreceive the caps 126 and 128 respectively which are provided with theports 127 and 129 respectively.

A helical spring 125 within the cap 126 is adapted to' engage the piston124 and tends to force the same downwardlyto seat the valve 120 upon theseat 119, as shown in Fig. 16, to cut off the communication between thetriple valve exhaust port 113and theatmosphere exhaust port 122.

Normally the parts of the automatic safety control are in the positionshown in Figs. l, 6, 8, 12 and 16. Air entering the conduit 25, seeFig.15, passes through the operators valve 110 into the conduit means 133,13 1, 135, 136 and 137, triple valve 112 into the auxiliary reservoir10. The air which simultaneously enters the chamber 18, see Fig. 6,passes into the chamber thence through the port 1-9" into the chamber 19and from there passes into the auxiliary reservoir 39, through theconduit 38. From the chamber -19 the air also enters the chamber 47throughthe ports 62, see Fig. 4., and passes through the chamber 17 intothe conduit and then into the brake cylinder 22 at 142, eusing thebrakes to be applied. As will be remembered the circuit breaker controlin its normal position prevents power from being supplied to thevehicle, consequently the vehicle would be inoperative since the brakesare applied and the power is shut 01f.

However, if the triple valve exhaust port control valve 11a were notprovidedthe air would not remain in the brake cylinder 22 but would passthrough the conduit 14:0 in to the triple valve and exhaust through theport 113, which is normally open. Since the normal position of thetriple valve exhaust port control valve is as shown in Fig. 16 the port121 is closed by the valve, 120 thereby preventing any air from escapingthrough the exhaust port 122, which preventsfthe brakes from beingreleased until suiiicient pressure is built up to insure safe brakingower.

hen, as in the straight air brake system suflicient pressure has beenbuilt up in the reservoirs 39 and 40 and the chamber 55, see Fig. 6, toovercome the tension of the spring 76, which acts to insure'safe brakingpower, air enters the passage 58, conduits 32 and 131 which causes thepiston 124, see Fig. 16, to move upwardly and open the port 121, seeFig. 15, which permits the air in the brake cylinder 22 to escape to theatmosphere through the triple valve exhaust port 113, conduit 118, port118*, chamber 117, port 121. chamber 116 and port,122, thereby releasingthe brakes. At the same time the air enters the circuit breaker control98 and causes the piston valve 90 to move, see Fig. .12 to operativeposition, shown in Fig. 11, which places the vehicle in operativecondition, that is the brakes on the'vehicle or train are in thereleased position and power can be supplied through the circuit breakerto the driving means, as described. a

As long pressure 'su'liicient to insure safe braking power is maintainedin the pneumatic circuit, the parts willremain in operative position andthe operator is free to apply and release the brakes in the usualmanner. Should, however, the pressurebe reduced below .the pressureexerted by the spring 76 in the automatic safety control valve 33, thebrakes would instantly be applied and the power simultaneously shut offin the manner hereinbefore mentioned. If the defect which caused thebrake application could not be readily repaired, it then would benecessary to drain theentire' brake system of all air through the drainvalve 139, see Fig. 15, provided as part of the regular equipment. Whenthe pneumatic tem is drained there is no pressure to main tain thecircuit breaker control in the operating or closed circuit position andit is necessary for the operator to use the manual operating means ofthe circuit breaker control hereinbefore described'to permitpower to besupplied to the-vehicle and also usethe hand brake on the vehicle forstopping the same.

While the automatic safety control valve 33 is illustrated and describedherein as applied to what is known as a straightair and the automaticair brake systems,it will be understood that many modifications of thevalve will suggest themselves to those skilled in the air brake art andthese modifications it will be understood are within the broad purview.of this invention. will be likewise understood that the .automaticsafety control valve 33. and-the various parts thereof may be appliedtoother air brake systems'not specifically mentioned in the foregoingspecifications by suitable. means which will suggest themselves to thoseskilled in this art. Although the selected em bodiment of the inventionhas been described in detail it will be understood that the broaderfeatures thereof .are not to be limited by said description, sincexthesame has been given so that a complete understanding of the device andmechanism will be more readily understood.

The invention claimed is:

1. A power operatedvehicle having a power circuit,fluid-pressure-controlled means for breaking the circuit,manuallyoperated means of said fluid-pressure-controlled means forrestoring said circuit, a device adapted to preventoperation of saidmanually operated means,- and aseal for said device substantially as set"forth.

2. A' power operated vehicle having a power circuit,fluid-pressure-controlled means for breaking the circuit,manuallyoperated means of said fluid-pressure-controlled means forrestoring said circuit, and means to lock said manually operated meansin place, substantially asset forth.

3. In a pneumatically operated brake system including a source ofpneumatic pres pneumatic pressure from said brake means and "adapted toconnect said auxiliary source of pressure to said brake means upon afailure of pressure in the original source of supply.

t. In a pneumatically operated brake system including a source ofpneumatic pressure brake means operable thereby, the combination'oi anauxiliary source of pneumatic pressure, means-connecting said auxiliarysource of neumatic pressure to the brake means, and single valve meansnormally maintaining a free passage from the original source ofpneumatic pressure to the brake means and normally disconnecting theauxiliary source of pneumatic pressure from said brake means and adaptedto connec't saidau'Xi-iiar source of pressure to said brake means upon afailure of pressure in the o'rigina1 source of supply.

5. In a pneumatically operated brake system including a source ofpneumatic pressure and brake means'opera-ble thereby, the

combinationof an auxiliary source of pneumatic pressure, meansconnecting said auxilia'ry "source of pneumatic pressure to the brakemeans, and valve means normally maintaining a free passage from the'origi-- nal source of pneumatic pressure to the brake means andnorm-ally disconnecting the auxiliary "source of pneumatic pressure from"said brake means and for connecting said auxiliary source of pressureto said brake-means upon a failure of pressure in the original source ofsup ply.- I

'6. In a power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination with means to apply the pneumatic brakes,

and means to shutv off 'the po'wer'supplied to the vehicle, of'mean'sfor operating both of said means upon a reduction in pressure from apredetermined pressure, means for locking. said operating means, andmeans for automatically releasing the locking means when a predeterminedpressure is re established.

-7. In a power propelledvehicle provided with a-pneum'atic brake system,including a source of pneumatic pressure and brake means o-perablethereby, the combination with mean s-toapply the pneumatic brakes, andmeans to shut off the power supplied to the veh'oicle, of means forsimultaneously op crating both ofsaic'l means upon a reduction orpressure from a predetermined pressure and pneumatic means for lockingsaid operating means and pneumatic means for automatically releasing thelOGkl'iIg means When a predetermined pressure is re-established.

8. A power operated vehicle having a power circuit, a circuit breaker,fluid-pressure-controlled means for operating the circuit breakerincluding a latch engaging the c'ircuitbreaker and releasable therefromon undue change of pressi'ir'e, and manual *mea ns for restoring saidlatch to operative position, substantially as set forth.

9. In a power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure andbrake means operablethereby, the combination with means to apply the brakes, and means for'supplying power to the vehicle, of an auxiliary source of pressure, andmeans operable by apneumatic-failure of the "brake system for applyingthe brakes and for ihultting off the power supplied to the ve- 10. In apower propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and 'br'a l'c'e means operablethereby, the combination with means to apply the brakes, and means forsupplying power to the vehicle, or means operable by "a neumaticfailureof the brake system for shi'itting off the pow-er supplied to thevehicle, "and means for tentiona'lly supplying power to "the vehiclenotwithstanding means. I

11. In a powerpropelled vehicle prow'fided with a pneumatic *brakesystem, "incli-i'dingg said power controlling a source ofpneumaticpressure and "brake means operable thereby, the combinationwith means to apply 'the brakes, and-means for supplyingpower to thevehicle, of means operable by a pneumatic failure of the prake systemfor shutting'oii the power-supplied to the vehicle, means forintentionally supplying power to the vehicle notwithstanding said powercontrolling me'ainsyand 'm'e'an's for regulating theoperation of saidfinten tional means.

'12. Ina power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, *the combination with means *forsupplying power to the vehicle,of means =operable by a pneumatic failure of the brake system forshutting-off the power'supplied to the vehicle, and "ad ditional meansfor shutting "off the power independently of said penumatic failureoperable means.

13. In a power propelled vehicle provided with'a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination with means for applying the brakes, and meansfor supplying power 'to' the vehicle, of an auxiliary source ofpressure, means operable by a pneumatic failure of the brake system forapplying the brakes and for shutting 01f the power supplied to thevehicle, and additional means for shutting off the power independentlyof said pneumatic failure operable means.

14. In a power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination with means for supplying power to the Vehicle,of means operable by a pneumatic failure of the brake system forshutting off the power supplied to the vehicle, means for lntentionallysupplying power notwithstanding said power controlling means, andadditional means for shutting off the power independently of saidpneumatic failure operable means and notwithstanding said intentionalpower supplying means.

15. In a power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination with means for applying the brakes and meansfor supplying power to the vehicle, of an auxiliary source of pressure,means operable by pneumatic failure, of the brake system for applyingthe brakes and for shutting off the power su'ppliedto the vehicle, meansfor releasing the-brakes and for intentionally supplying powernotwithstanding said pneumatic failure operable means, and additionalmeans for shutting off the power independently of said pneumatic failureoperable means and notwithstanding said intentional supplying means.

16. In a power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby,the combination with means for applying the brakes and means forsupplying power to the vehicle, of an auxiliary source of pressure,means operable by pneumatic failure of the brakesystem for applying thebrakes and for shutting off the power supplied to the vehicle, singlemeans for releasing the brakes and for intentionally supplying powernotwithstand ing said pneumatic failure operable means.

17. In a power propelled yehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination with means for applying the brakes and meansfor supplying power to the vehicle, of an auxiliary source of pressure,means operable by pneumatic failure of the brake system for applying thebrakes and for shutting oil the power supplied to the vehicle,

power notwithstanding said pneumatic failure operable means, andadditional means for shutting off the power independently of saidpneumatic failure operable means and notwithstanding said intentionalsupplying means. 18. In a power propelled vehicle provided with apneumatic brake system, including a source of pneumatic pressure and;brake means operable thereby, the combination with means for applyingthe brakes and means for supplying power to the ,vehicle,-of anauxiliary source of pressure, and means operable by pneumatic failure ofthe brake system for applying the brakes and for'shutting off the powersupplied to the vehicle, means for releasing the brakes and forintentionally supplying power notwithstanding said pneumatic failureoperable means, additional means for shutting off the powerindependently of said pneumatic failure operable means andnotwithstanding said intentional supplying means, and means forrecording the intentional supplying of power to said vehicle. r

19. In a power propelled vehicle providedwith a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination with means for applying. the brakes, and meansfor supplying power to the vehicle, of an auxiliary source of pressure,means operable by pneumatic ffailure of'thelbrake system for applyingthe brakes and for shutting off the power-supplied to the vehicle,single means for releasingthe brakes and for intentionally supplyingpower notwithstanding said pneumatic failure operable means, and meansfor recording the intentional supplying of power to said vehicle.

20. A safety control system for a pneumatic brake system including anauxiliary reservoir for pneumatic pressure and a safety controlvalve'interposed in the pneumatic brake system for charging saidauxiliary. reservoir and for, discharging the same into the brake systemto operate the brakes independently of the pneumatic brake sys 21. In acontrol system a-control valve including a chamber, a fluid operatedpiston therein, a second chamber, a second fluid operated piston in saidsecond chamber, a rod supporting both pistons, and means for operatingsaid rodwto actuate one ofsaid pistons, i 1

22. In a control system a control valve includingachamber, a fluidoperated piston therein, asecond chamber, a second fluid operated pistonin said second chamber, a

rod supporting both pistons, means. for operating said rod to actuateboth of said pistons. i

arm

23. In a control system, a controlvalve' including two chambersofdiiierent sizes, a piston in each chamber, pneumatic meanscommunicatingwith both chambers and oppositely directed against saidpistons, and

means for actuating the smallerpiston when supporting both pistons,pneumatic. :means communicating with both chambers, said pistons beingoppositely directed by said pneumatic means, means maintaining thesmaller piston in a position similar to the larger piston in oppositionto said pneu-v matic pressure whereby upon the release of the pressurein the larger chamber said smallerpiston is actuated by the pressure inthe smaller chamber. .v

25. In a control system a control valve in eluding two chambersofdifferent sizes, a piston in each chamber, a source of pneumaticpressure communicating with one chamber, a second source of pneumaticpressure communicating with the other chamber.

said pressures being substantially equal, said pistons being oppositelydirected by said pressures, and means connecting sald pistons wherebythe pressure exerted upon the larger piston maintains the smaller pistonin a given position, the smaller'piston being actuated whenthe pneumaticpressure is released from the larger chamber.

, 26. In a safety control system forpower propelled vehicles, thecombination of power controlling means, means for actuating'said powercontrolling means to open the power circuit, pneumatic means fornormallymaintaining said actuating means in the closed circuitposition,and :means for actuating said power. controlling means to open the powercircuit independently of tic power maintaining means. v

27. In'a safety control system for power propelled vehicles, thecombinationof power controlling means, means for actuating saidpower-controlling means to open the power circuit, pneumatic means fornormally maintaining said actuating means in the closed circuitposition, and means for locking said pneumatc means-'inthe closedcircuit position. 1

28. In a safety control system for power the pneumas independently ofthe pneumatic maintaining means and said locking means.

29. In a safetycontro'l-system for power propelled vehicles, thecombination of power controlling means,means for actuating said powercontrolling means to open the power circuit, pneumatic means fornormally maintaining said means in the closed circuit position, meansfor locking said pneumatic means in the closed circuit position, and recording means for registering the operation of said locking means whenthe latter is moved to the locking position.

30. In a safety control system for power propelled vehicles, thecombinationof power controlling means,'means for actuating said powercontrolling means to open the power circuit, pneumatic means fornormally maintaining said actuating means' in the closed circuitposition, means for locking said pneumatic means in the closed circuitposition, recording means for registering the operation of said lockingmeans when the latter is moved to the locking position, and means foractuating said power controlling means to open the power circuitindependently of the pneumaticmaintaining means and the locking means. I

31. In a safety control system for a pneu- I matic brake system, thecombination with a source of pneumatic pressure and brake means operablethereby, of an auxiliary reservoir communlcatlng with the originalsource of pressure for storage purposes, check valve-means-insaid lineof communication, and means interposed in the communication between theoriginal source of pressure and the brake means, said means beingadapted to open communication between said auxiliary reservoir and saidbrake means to operate the latter upon a decrease in pressure insaidsource of-pneumatic pres sure below a predetermined pressure.

32. In a safety control system for a pneu I matic. brake system thecombination with a source of pneumatic pressure and brake means operablethereby, of pneumatically operated valve means controlling the-communica'tion between said source of pneu matic pressure and the brakemeans, and means for controlling the operation-of said valve means.-

I 33. In a safety control system for pneumatic brake system,-thecombination with a source of pneumaticpressure and brake means operablethereby, of valve means con trolling the communication between saidsource of pneumatic pressure and the brake means, means controlling theoperation of said valve 1nean's,'said-' means including a pneumaticallymaintained'valve, and means for actuating said pneumatically maintainedvalve upon a reduction in pressure below a predetermined pressure in thepneumatic circuit.

3a. In a safety control system fora pneumatic brake system, thecombination with a source of pneumatic pressure and brake means operablethereby, of valve means controlling the communication between saidsource of pneumatic pressure and the brake means, means controlling theoperation of said valve means, said means including a pneumaticallymaintained valve, means for actuating said pneumatically maintainedvalve, upon a reduction in pressure below a predetermined pressure insaid pneumatic circuit, and adjustable means for varying thepredetermined pressure limit.

35. In a safety control system for a pneumatic brake system, thecombination with a source of pneumatic pressure and brake meansoperable'thereby, of valve means controlling the communication betweensaid source of pneumatic pressure and the brake means, means controllingthe operation of said valve means, said means including apneumaticallymaintained valve, and means for actuating saidpneumatically maintained valve upon a reduction in pressure below apredetermined pressure in said pneumatic circuit, and means foractuating said first mentioned valve means and operable upon a failureof said pneumatically maintained valve actuating means.

36. Ina power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination of an auxiliary source of pneumatic pressure,means for controlling the power supplied to the vehicle, and safetycontrol means associated with said power controlling means and saidsource of pneumatic pressure for maintaining the brakes in the appliedposition and preventing the supply of power to the vehicle until apredetermined safe braking pressure is established in'the brake system,said safety control means being operable at said predetermined pressureto release the brakes and said power controlling 'means, said safetycontrol means then being operable by a pneumatic failure of the brakesystem to apply the brakes and prevent power being supplied to saidvehicle. I

37. In a powerpropelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination of an auxiliary source of pneumatic pressure,means for controlling the power supplied to the vehicle, and safetycontrol means associated with said power controlling means and saidsource of pneumatic pressure for maintaining the brakes in the appliedposition and preventing the supply of power to the vehicle until apredetermined safe brak-i ing pressure is established in the brakesystem, said safety control 'means being operable at said predeterminedpressure to re lease the brakes and said power controlling means, saidsafety control means .thenbeing operable by a failure of the safetycontrol means for preventing power to be supplied to the vehicle. I a

38. In a power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake,

means operable thereby, thecombination of an auxiliary source ofpneumatic pressure,

means controlling the power supplied to the vehicle, and safety controlmeans for apply? ing the brakes and preventing power being supplied tothe vehicle, said safety control means being operable to release thebrakes when a predetermined pressure has been established in theoriginal brake system."

39. In a power propelled vehicle provided with a pneumatic brake system,including a source of pneumatic pressure and brake means operablethereby, the combination of an auxiliary source of pneumatic pressure,

means controlling the power supplied to the vehicle, and safety controlmeans for applying the brakes and preventing power. being supplied tothe vehicle, said safety control means being operable to release thebrakes and operate the power controlling means to permit power tobe'supplied to the vehicle when a predetermined pressure has beenestablished in the original brake system;

40. Ina'power propelled vehicle provided with a pneumatic brake system,includinga source of pneumatic pressure and brake means operablethereby, the combination of an auxiliary source of pneumatic pressure,

means controlling the power supplied to the vehicle, and safety controlmeans for applying the brakes and preventing power being supplied to thevehicle, said safety control means being operable to release the brakesand operate the power controlling means to permit power to be suppliedto the vehiclev when a predetermined pressure has been established inthe original brake system, and, means associated with said auxiliarysource of pressure and" said power controlling means for controllingsaid safety control means to permit the operation of the vehicle.

41. In a power propelledvehicle provided with a pneumatic brake system,"including a source of pneumatic pressure and brake means operablethereby, the combination "of an auxiliary source of pneumatic pressure,means controlling the power supplied to the vehicle, and safety controlmeans for applying the brakes and preventing power being supplied to thevehicle, said I safety control means beingoperable to release the brakeswhen" a predetermined pressure has been established in the originalbrake system, and means associated with said auxiliary source ofpressure for controlling fthe safety control means to permit theopera-tion of the vehicle.

42.'In a brake system, the combination with a source of pneumaticpressure and brake means operable thereby, including a v triple valvehaving an exhaustport, the

combination of an auxiliary source of pneu matic pressure, valve meanscontrolling said triple valve exhaust port, and safety control meansassociated with said valve controlling means for maintaining said portin closed position until a predetermined safe operating pressure hasbeen established in the brake system.

4-3, In a brake system the combination with a source of pneumaticpressure and brake means operable thereby, including a triple valvehaving an exhaust port, the combination of an auxiliary source ofpneumatic pressure, valve means controlling said triple valve exhaustport, and safety control means associated with said valve con-.

trolling means for maintaining the brakes in the applied position andsaid port-in the closed position until a predetermined safe operatingpressure has been established in the brake system. 44.11! a brake systemthe combination with a source of pneumatic pressure and brake meansoperable thereby, including a triple valve having an exhaust port, thecombination" of an auxiliary source of pneumatic pressure, valve meanscontrolling said triple valve exhaust port, and safety con trol meansassociated with said valve controlling means for maintaining the brakesv in the applied position and said port in the closed position until apredetermined safe operatlng pressure has been established in the brakesystem, said safety control means being operable upon a failure of thebrake system and being associated with said triple valve control meansfor applying the brakes and closing said port and maintaining the samein said positions until a predetermined safe operating pressure has beenr'e-established in the brake system.

-45. In a power propelled vehicle provided with apneumatic brake systemincluding a source of pneumatic pressure and brake means operablethereby, including atriple valve having an exhaust :port, the combination of an auxiliary source of pneumatic pressure, means for controllingthe power 7 supplied to the vehicle, valve means con trolling saidtriple valve exhaust port, and safety control means associated with saidpower controlling means, brake means and said exhaust port control lingvalve means to maintain the brakes in :the applied position andtoprevent the o supply of power to the vehicle until a predetermined safebraking, pressure is establishedin the brake system, said safety controlmeans being operable at said predetermined pressure upon saidexhaustport for releasing said brakes and said power con-i trolling means.

with a pneumatic brake system includinga source of pneumatic pressureand brake means operable thereby, including a triple valve having anexhaust port, the combination of an auxiliary source of pneumaticpressure, means for controlling the power supplied to the vehicle, valvemeans controlling said triple valve exhaust port, and safety controlmeans associated with said power controllmg means, brake means and saidexhaust part controlling val-vex means to,

maintain the brakes in the applied position, to prevent the supply ofpower to the vehicle until a predetermined safe braking pres sure isestablished in the brake system, said safety control means beingoperable at said" predetermined pressure upon "said exhaust port forreleasing tsaid brakes and said power controlling means, said safetycontrolling means then being operable by pneu safety control meansassociated with said' power controllmgmeans, brake means and saidexhaust port controlling valve means to maintain the brakes in theapplied position and to prevent the supply of power to the vehicleuntil, a predeterminedv safe braking pressurev is established in'thebraking system,said safety control means being opera ble at saidpredetermined pressure upon said exhaust port for releasing said brakeand saidppower controlling means, said safety controlling meansthen-being; operable by a pneumatic 'failureof the brake system to closesaid triple valve exhaust port, apply saidbrakes and prevent power to'besupplied to said vehicle, said safetycontrolling means being operabletoopen saidclosed port, relea'sesaid brakesand permit power to besupplied to saidvehicle when the predetermined safe operating pressureis "re-es tablished inthe brake system.

48, In a power propelled vehicle provided with a pneumatic brake systemincluding a source of pneumatic pressurewand brake means operablethereby, including a triple valve having anexhaus't port, the combina-46. In power propelled vehicle provided tion of an auxiliary source ofpneumatic pressure, means for controlling the power supplied o thevehicle, valve means con trolling said triple valve exhaust port, and

safety control means associated with said power controlling means, brakemeans and said exhaust port controlling valve means to maintain thebrakes in the applied position and to prevent the supply of power to thevehicle until a predetermined safe braking pressure is established inthe brakingsystem, said safety control means being operable at saidpredetermined pressure upon said exhaust port for releasing said brakesand said power controlling means, said safety controlling means thenbeing operable by a pneumatic failure of the brake system to close saidtriple valve exhaust port, apply said brakes and prevent power to besupplied to said vehicle, and means associated with said auxiliarysource of pressure and said power controlling means for controlling saidsafety control means to permit the operation of the vehiclenotwithstanding the operation of said safety control means to maintainsaid brakes in the applied position and prevent power to be supplied tosaid vehicle.

49, In a power propelled vehicle provided with apneumatic brake system,including a source of pneumatic pressure and brake means'operablethereby, the combination of an auxiliary source of pneumatic pressureand means for controlling the power supplied to the vehicle, and safetycontrol means associated with said power controlling means and saidsourceof pneumatic pressure for maintaining the brakes in the appliedposition and preventingthe power supplied to the vehicle until apredetermined safe braking pressure is established in the brake system,said safety control means being operable at said predetermined pressureto release the brakes and said brake control means, said safety controlmeans then being operable by a failure of the-safety control means toapply the brakes and prevent power being supplied to the vehicle.

In witnesswhereof, we have hereunto affixed our signatures.

' T LUI F. HELLMANN.

WILLIAM W. BAXTER.

